A green pointer I bought a year ago from Laser Pointer Pro has started producing a smudged dot. It's fine for about 10 seconds, then a halo-smudge type effect surrounds the dot. Any clues?
Yes, most likely mode hopping shifting the position of the beam, causing it to hit the lens ring. Not really much you can do about this apart from trying to realign the crystals so it doesn't hit.
OK thanks., argh, mode hopping. Would post a photo, but don't have a digital camera, and my computer's built-in cam doesn't capture laser light well at all.